企业运维实战--k8s学习笔记 通过Ingress-nginx实现k8s七层负载均衡、Ingress加密、认证以及地址重写

一种全局的、为了代理不同后端 Service 而设置的负载均衡服务，就是 Kubernetes 里的Ingress 服务。

Ingress由两部分组成：Ingress controller和Ingress服务。

Ingress Controller 会根据你定义的 Ingress 对象，提供对应的代理能力。业界常用的各种反向代理项目，比如 Nginx、HAProxy、Envoy、Traefik 等，都已经为Kubernetes 专门维护了对应的 Ingress Controller。

ingress服务的使用必须在策略网络中才能实现，如calico网络

ingress相当于一个7层的负载均衡器，是k8s对反向代理的一个抽象。大概的工作原理也确实类似于Nginx，可以理解成在 Ingress 里建立一个个映射规则 , ingress Controller 通过监听 Ingress这个api对象里的配置规则并转化成 Nginx 的配置（kubernetes声明式API和控制循环） , 然后对外部提供服务。ingress包括：ingress controller和ingress resources

ingress controller：核心是一个deployment，实现方式有很多，比如nginx, Contour, Haproxy, trafik, Istio，需要编写的yaml有：Deployment, Service, ConfigMap, ServiceAccount（Auth），其中service的类型可以是NodePort或者LoadBalancer。

ingress resources：这个就是一个类型为Ingress的k8s api对象了，这部分则是面向开发人员。

mkdir ingress
cd ingress/
下载所需要的deploy.yaml
vi deploy.yaml

image: ingress-nginx/controller:v1.0.3
image: ingress-nginx/kube-webhook-certgen:v1.5.1

在自己的仓库中添加公开项目ingress-nginx专门存放相关的镜像

执行deploy.yaml清单，查看ns状态

kubectl apply -f deploy.yaml
kubectl get ns

查看ingress-nginx的所有信息，可以看到ingress-nginx-controller已经running
kubectl -n ingress-nginx get all

查看svc暴露端口
kubectl -n ingress-nginx get svc

测试：访问server1ip地址加上端口

3.1创建pod：nginx myapp

vi deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: myapp:v1
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
  labels:
    app: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: myapp:v2

拉起deployment，通过标签来锁定域名

3.2配置添加svc服务
vi svc.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx-svc
spec:
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  selector:
    app: nginx
---
apiVersion: v1
kind: Service
metadata:
  name: myapp-svc
spec:
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80
  selector:
    app: myapp

拉起服务并查看endpoint
应用yaml文件，创建服务
kubectl apply -f svc.yaml

查看服务信息
kubectl get svc

修改svc配置文件为负载均衡

kubectl -n ingress-nginx edit svc ingress-nginx-controller

查看修改内容
kubectl -n ingress-nginx get svc
external-ip 为 172.25.76.10
3.3服务与ingress连接，并给定域名 ,用于匹配service

vi ingress.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-nginx
spec:
  rules:
  - host: www1.westos.org
    http:
      paths:
      - pathType: Prefix
        path: "/"
        backend:
          service:
            name: nginx-svc
            port:
              number: 80
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-myapp
spec:
  rules:
  - host: www2.westos.org
    http:
      paths:
      - pathType: Prefix
        path: "/"
        backend:
          service:
            name: myapp-svc
            port:
              number: 80

拉起资源清单

kubectl apply -f ingress.yaml

查看ingress反向代理信息

kubectl get ingress

测试机添加解析到服务节点172.25.76.10

vi /etc/hosts 

172.25.76.10 www1.westos.org www2.westos.org

访问测试：

[root@foundation76 ingress]# curl  www2.westos.org
Hello MyApp | Version: v2 | Pod Name
[root@foundation76 ingress]# curl  www1.westos.org
Hello MyApp | Version: v1 | Pod Name

因为认证需要系统自带的认证功能！
所以需要安装生成认证整数的插件

yum install -y httpd-tools

生成证书，输入认证密码
创建证书到k8s secret

htpasswd -c auth lcf #生成证书，输入认证密码
kubectl create secret generic basic-auth --from-file=auth
# 创建证书到k8s secret
kubectl get secrets

编辑文件ingress.yaml导入证书

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-nginx
  annotations:
    nginx.ingress.kubernetes.io/auth-type: basic
    nginx.ingress.kubernetes.io/auth-secret: basic-auth
    nginx.ingress.kubernetes.io/auth-realm: 'Authentication Required - lcf'
spec:
  tls:
  - hosts:
    - www1.westos.org
    secretName: tls-secret
  rules:
  - host: www1.westos.org
    http:
      paths:
      - pathType: Prefix
        path: "/"
        backend:
          service:
            name: nginx-svc
            port:
              number: 80
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-myapp
  annotations:
    nginx.ingress.kubernetes.io/auth-type: basic
    nginx.ingress.kubernetes.io/auth-secret: basic-auth
    nginx.ingress.kubernetes.io/auth-realm: 'Authentication Required - lcf'
spec:
  tls:
  - hosts:
    - www2.westos.org
    secretName: tls-secret
  rules:
  - host: www2.westos.org
    http:
      paths:
      - pathType: Prefix
        path: "/"
        backend:
          service:
            name: myapp-svc
            port:
              number: 80

执行ingress.yaml文件

kubectl apply -f ingress.yaml

访问测试

curl -k https://www1.westos.org -u lcf:westos
Hello MyApp | Version: v1 | Pod Name

修改文件ingress.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-nginx
  annotations:
    nginx.ingress.kubernetes.io/auth-type: basic
    nginx.ingress.kubernetes.io/auth-secret: basic-auth
    nginx.ingress.kubernetes.io/auth-realm: 'Authentication Required - lcf'
    nginx.ingress.kubernetes.io/app-root: /hostname.html
spec:
  tls:
  - hosts:
    - www1.westos.org
    secretName: tls-secret
  rules:
  - host: www1.westos.org
    http:
      paths:
      - pathType: Prefix
        path: "/"
        backend:
          service:
            name: nginx-svc
            port:
              number: 80
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-myapp
  annotations:
    nginx.ingress.kubernetes.io/auth-type: basic
    nginx.ingress.kubernetes.io/auth-secret: basic-auth
    nginx.ingress.kubernetes.io/auth-realm: 'Authentication Required - lcf'
    nginx.ingress.kubernetes.io/app-root: /hostname.html
spec:
  tls:
  - hosts:
    - www2.westos.org
    secretName: tls-secret
  rules:
  - host: www2.westos.org
    http:
      paths:
      - pathType: Prefix
        path: "/"
        backend:
          service:
            name: myapp-svc
            port:
              number: 80

再次执行文件ingress.yaml,查看信息：

kubectl apply -f ingress.yaml
kubectl describe ingress

访问www1.westos.org发现自动重定向到了www1.westos.org/hostname.html